Chemokines
Chemokines are a superfamily of forty or more small (approximately about 4 to about 14 kDa) inducible and secreted pro-inflammatory cytokines that act primarily as chemoattractants and activators of specific leukocyte cell subtypes. Together, chemokines target the entire spectrum of leukocyte subtypes; individually each targets only part of the spectrum. Chemokines, which are basic heparin-binding proteins, have four cysteines shared among almost all family members. There are four major groups of chemokines, three of which include the four conserved cysteines. The groups are defined by the arrangement of the first two cysteines. If the first two cysteines are separated by a single amino acid they are members of the CXC family (also called a); if the cysteines are adjacent, they are classified in the CC family (also called B). If they are separated by three amino acids CX3C, they are members of the third group. The fourth group of chemokines contains two cysteines, corresponding to the first and third cysteines in the other groups. Structural analysis demonstrates that most chemokines function as monomers and that the two regions necessary for receptor binding reside within the first 35 amino acids of the flexible N-terminus (Clark-Lewis et al. (1995) J Leukoc Biol 57, 703–11; Beall et al. (1996) Biochem J 313, 633–40; and Steitz et al. (1998) FEBS Lett 430, 158–64).
Chemokines, in association with adhesion molecules, recruit subsets of leukocytes to specific sites of inflammation and tissue injury. Generally, chemokines and chemokine receptor expression are up-regulated in disease, with chemokines acting in an autocrine or paracrine manner (Glabinski et al., Int. J. Dev. Neurosci., 13: 153–65, 1995; Furie and Randolph, Am. J. Pathol., 146: 1287–301, 1995; Benveniste, E. N., J. Mol. Med., 75: 165–73, 1997; Schall et al., Current Biol., 6: 865–73, 1994; Taub et al., Ther. Immunol., 1: 229–46, 1994; Baggliolini et al., Adv. Immunol., 55: 97–179, 1994; and Haelens et al., Immunobiol., 195: 499–521, 1996). Several cytokines and chemokines work together to regulate most functions of mononuclear phagocytes (MNPs; monocytes), including the release of neurotoxic and cytotoxic factors.
Once secreted by infiltrating mononuclear phagocytes (MNPs), particularly, such as activated microglia, a distinct class of mononuclear phagocytes (MNPs) found in the CNS, chemokines are responsible for the chemoattraction of several other leukocyte cell types, including neutrophils, eosinophils, basophils, T-lymphocytes, and natural killer cells. In vitro studies have shown that various stimuli, including lipopolysaccharide (LPS), IL-1, IFN-γ and TNF-α induce the expression and secretion of chemokines from various central nervous system (CNS) and other cell types (Proost et al., J. Leukoc. Biol., 59: 67–74, 1996; Graves et al., Crit. Rev. Oral Biol. Med., 6: 109–18, 1995; Hayashi et al., J. Neurommunol. 60: 143–50, 1995; and Hurwitz et al., J Neuroimmunol., 57: 193–8, 1995). For example, production of chemokines such as monocyte chemotactic protein-1 (MCP-1), macrophage inhibitory protein-1 (MIP-1β), and RANTES (Regulated on Activation, Normal T cell Expressed and Secreted) can be induced from astrocytes, microglia and leukocytes (Proost et al., J. Leukoc. Biol., 59: 67–74, 1996; Graves et al., Crit. Rev. Oral Biol. Med., 6: 109–18, 1995; Hayashi et al., J. Neurommunol. 60: 143–50, 1995; and Hurwitz et al., J Neuroimmunol., 57: 193–8, 1995). These chemokines have been shown to induce chemotaxis and activation of microglia and macrophages in cell culture studies (Graves et al., Crit. Rev. Oral Biol. Med., 6: 109–18, 1995; Hayashi et al., J. Neurommunol. 60: 143–50, 1995; and Hurwitz et al., J Neuroimmunol., 57: 193–8, 1995; Sun et al., J. Neurosci. Res., 48: 192–200, 1997; and Peterson et al., J. Infect. Dis., 175: 478–81, 1997). Thus, chemokines are thought to induce the production and release of reactive oxygen species, degradative enzymes, and inflammatory and toxic cytokines from various leukocyte and MNP cell populations (Glabinski et al., Int. J. Dev. Neurosci., 13: 153–65, 1995; Furie and Randolph, Am. J. Pathol., 146: 1287–301, 1995; Benveniste, E. N., J. Mol. Med., 75: 165–73, 1997; Schall et al., Current Biol., 6: 865–73, 1994; Taub et al., Ther. Immunol., 1: 229–46, 1994; Proost et al., J. Leukoc. Biol., 59: 67–74, 1996; Graves et al., Crit. Rev. Oral Biol. Med., 6: 109–18, 1995; Hayashi et al., J. Neurommunol. 60: 143–50, 1995; Hurwitz et al., J Neuroimmunol., 57: 193–8, 1995; Sun et al., J. Neurosci. Res., 48: 192–200, 1997; Peterson et al., J. Infect. Dis., 175: 478–81, 1997; Leonard et al., Immunol. Today, 11: 97–103, 1990 and Fahey et al., J. Immunol., 148: 2764–9, 1992; Ali et al., Adv. Rheumatol., 81: 1–28, 1997).
The chemokine members MCP-1, MIP-1β, and RANTES have been shown to be expressed in astrocytes and macrophages after mechanical injury to the brain (Glabinski et al., Int. J. Dev. Neurosci., 13: 153–65, 1995; and Ghirnikar et al., J. Neurosci. Res., 46: 727–33, 1996). In these studies, the expression of the chemokines under investigation correlated with the onset of reactive gliosis and the appearance of MNPs at the site of injury. MCP-1 and MIP-1α expression has been detected in MNPs and astrocytes after focal cerebral ischemia in the rat (Kim et al., J. Neuroimmunol., 56: 127–34, 1995; Gourmala et al., J. Neuroimmunol., 74: 35–44, 1997; and Takami et al., Neurosci. Lett., 277: 173–6, 1997), and several investigators have studied the expression of various chemokines in EAE, an animal model for multiple sclerosis (MS; Berman et al., J. Immunol., 156: 3017–23, 1996; and Adamus et al., J. Neurosci. Res., 50: 531–8, 1997). Also, transgenic mice that over-express MCP-1 have been shown to exhibit pronounced MNP and leukocyte infiltration into the CNS (Fuentes et al., J. Immunol., 155: 5769–76, 1995).
The expression levels of numerous cytokines and chemokines have been reported to be elevated in and modulate the progression of countless cancer types (Van Mier, Glia, 15:264–88, 1995). For example, leukemic human mast cells appear to be the source of multiple chemokines including; MCP-1; I-309; MIP-1α; MIP-1β; RANTES and IL-8. One study reports that normal human adult tissues express very low levels of RANTES, but expression was greatly increased in numerous types of cancers including lymphomas (von Luettichau, et al., Cytokine, 8:89–98). Similarly, MCP-3 expressions levels are increased in many tumor cell lines (Murakami, et al., DNA Cell Biol. 16:173–83).
Cytokines (e.g., IL-1, IL-6, and TNF-α) and chemokines (e.g., IL-8, MCP-1, MIP-1α, MIP-1β and RANTES) have been implicated in the pathology of numerous conditions and diseases, including secondary cellular damage. They have been implicated in the pathology of inflammatory joint diseases including rheumatoid arthritis (Rathanaswami et al., J. Biol. Chem. 268: 5834–9, 1993; Badolato and Oppenhiem, Semin. Arthritis Rheum., 2: 526–38, 1996; De Benedetti et al., Curr. Opin. Rheumatol., 9: 428–33, 1997; Viliger et al., J. Immunol., 149: 722–27, 1992; Hosaka et al., Clin. Exp Immunol., 97: 451–7, 1994; Kunkel et al., J. Leukoc. Biol., 59: 6–12, 1996). The release of inflammatory mediators including reactive oxygen species, proteolytic enzymes, and a variety of cytokines from MNPs are associated with the initiation and maintenance of tissue damage in the arthritic state (Kunkel et al., J. Leukoc. Biol., 59: 6–12, 1996; Badolato and Oppenhiem, Semin. Arthritis Rheum., 2: 526–38, 1996).
Chemokine Receptors
Chemokines mediate their activities via G-protein-coupled cell surface receptors. Five receptors (CXCR1–5) to which CXC chemokines bind and ten receptors (CCR1–9, including CCR-2A and CCR-2B) to which CC chemokines bind have been identified. One member, designated Duffy antigen receptor, binds to CC and CXC chemokines.
Inflammatory cells, such as microglia, express several chemokine receptors, and more than one chemokine may bind to one receptor. For example, the β-chemokine receptor CCR3 (He et al., Nature, 385: 645–49, 1997) binds to not only MCP-3, MCP-4 and RANTES, but also to two other CC chemokines, eotaxin and eotaxin-2 (Jose et al., J. Exp. Med., 179: 881–7, 1994; Jose et al., Biochem. Biophys. Res. Commun., 205: 788–94, 1994; Ponath et al., J. Clin. Invest., 97: 604–12, 1996; Daugherty et al., J. Exp. Med. 183: 2349–54, 1996; and Forssman et al., J. Exp. Med., 185: 2171–6, 1997). Eotaxin and eotaxin-2 are CCR3-specific (Ponath et al., J. Clin. Invest., 97: 604–12, 1996; Daugherty et al., J. Exp. Med. 183: 2349–54, 1996; and Forssman et al., J. Exp. Med., 185: 2171–6, 1997).
A second example is the α-chemokine CXCR4 (fusin) HIV co-receptor. Three chemokines (stromal cell-derived factors SDF-1α (SEQ ID No. 32), SDF-1β (SEQ ID No. 93), and SDF-2) have been identified that specifically bind to this receptor, which is present on various subsets of inflammatory cells and are highly potent MNP cell attractants (Ueda et al., J. Biol. Chem., 272: 24966–70, 1997; Yi et al., J. Virol., 72: 772–7, 1998; Shirozu et al., Genomics, 28: 495–500. 1995; Shirozu et al., Genomics, 37: 273–80, 1996; Bleul et al., J. Exp. Med., 184: 1101–9, 1996; Tanabe et al., J. Immunol. 159: 905–11, 1997; and Hamada et al., Gene, 176: 211–4, 1996).
Inflammatory Disease, Secondary Tissue Damage and Chemokines
Chemokines have a variety of biological activities. They were initially isolated by their ability to stimulate leukocyte migration and activation. They have been shown to regulate negative hematopoietic progenitor proliferation, and several CXC chemokines can regulate angiogenesis. They may play a role in many diseases that involve inflammatory tissue destruction, such as adult respiratory distress syndrome, myocardial infarction, rheumatoid arthritis, and atherosclerosis.
Inflammatory responses are mediated by immune defense cells that accumulate at the site of tissue injury or trauma to rid the body of unwanted exogenous agents (e.g., microbes) or endogenous agents (e.g., cancer cell clones); to clean up cellular debris, and to participate in tissue and wound healing. Unfortunately, the molecular mechanisms involved in these reparatory (inflammatory) processes can initiate secondary tissue damage, which, in turn, contributes to the pathogenesis and persistent pathology of several inflammatory diseases. The molecular mechanisms and the cellular and chemical mediators involved in secondary tissue damage are similar, if not identical, in most inflammatory diseases of man. As an example, the processes involved in secondary tissue damage in central nervous system (CNS) trauma and disease are outlined below.
Studies on spinal cord injury (SCI) and generalized central nervous system (CNS) trauma have demonstrated a clear onset of secondary tissue damage that is observed within a matter of hours, may proceed for several weeks, and is followed by a period of partial recovery. Numerous factors are involved in the spread of secondary damage in spinal cord after traumatic injury, including ischemia, edema, increased excitatory amino acids, and oxidative damage to the tissue from reactive oxygen species. Neutrophils and macrophages can produce reactive oxygen species when activated and thus may contribute to the lipid peroxidation that occurs after spinal cord injury. Secondary tissue damage is detectable as cell death, astrogliosis that leads to glial scarring, neovascularization, demyelination, and loss of sensory and motor functions, i.e., paralysis. The time course of secondary damage and partial recovery are correlated with the degree of inflammation at the site of injury (Blight, A. R., J. Neurol. Sci. 103: 156–71, 1991; Dusart et al, Eur. J. Neurosci. 6: 712–14, 1994; and Gehrmann et al., Brain Res. Rev., 20: 269–87, 1995), and the molecular mechanisms that underlie these events appear to be similar to those that mediate the damage associated with other inflammatory diseases of the CNS, including multiple sclerosis, encephalomyelitis, Alzheimer's disease (AD), AIDS dementia complex, spongiform encephalopathies, and adrenoleukodystrophy (Raine, C. S., J. Neuropathol. Exp. Neurol., 53: 328–37, 1994; Sobel, R. A., Neurol. Clin., 13: 1–21, 1995; Dickson et al., Glia 7: 75–83, 1993; Benveniste, E. N., Res. Publ. Assoc. Res. Nerv. Ment. Dis., 72: 71–88, 1994; Benveniste, E. N., J. Mol. Med., 75: 165–73, 1997; Sippy et al., J. Acquir. Defic. Syndr. Hum. Retrovirol., 10: 511–21, 1995; Giulian et al., Neurochem, Int., 27: 119–37, 1995a; Christie et al., Am. J. Pathol., 148: 399–403, 1996; El Khoury et al., Nature 382: 716–19, 1996; Powers, J. M., J. Neuropathol. Exp. Neurol., 54: 710–9, 1995; and Ühleisen et al., Neuropathol. App. Neurobiol., 21:505–517, 1995).
It is generally accepted that microglia are the resident immuno-effector cells of the CNS (Gehrmann et al, Brain Res. Rev., 20: 269–87, 1995; Giulian, D., J. Neurosci. Res., 18: 155–171, 1987; and Giulian et al., J. Neurosci., 15: 7712–26, 1995b). Microglia and infiltrating macrophages, another class of MNP activated after injury, lead to secondary cellular damage (Giulian et al, J. Neurosci., 9: 4416–29, 1989; Giulian et al., Ann. Neurol., 27: 33–42, 1990; Gehrmann et al., Brain Res. Rev., 20: 269–87, 1995; Sobel, R. A., Neurol. Clin., 13: 1–21, 1995; Dickson et al., Glia 7: 75–83, 1993; Benveniste, E. N., Res. Publ. Assoc. Res. Nerv. Ment. Dis., 72: 71–88, 1994; Sippy et al., J. Acquir. Defic. Syndr. Hum. Retrovirol., 10: 511–21, 1995; and Giulian et al., Neurochem, Int., 27: 119–37, 1995a) by production and secretion of a number of pro-inflammatory cytokines and neurotoxic and other cytotoxic factors, and by de novo expression of cell surface immunomolecules.
Microglia produce and secrete the cytokine interleukin 1 (IL-1), which promotes the proliferation of astroglia in vitro (Giulian et al., J. Neurosci., 8: 709–14, 1988). Studies have shown that intracerebral infusion of IL-1 can stimulate astrogliosis and neovascularization that can only be detected after the appearance of microglia and macrophages at the site of injury (Giulian et al., J. Neurosci., 8: 2485–90, 1988; and Giulian et al., J. Neurosci., 8: 709–14, 1988). The greatest number of microglia and blood-borne macrophages appear 1–2 days after CNS trauma, which is the time period that has been associated with the peak production of IL-1 (Giulian et al., J. Neurosci., 9: 4416–29, 1989). Collectively, this evidence suggests that MNPs are responsible for stimulating astrogliosis via IL-1. In addition, activated microglia secrete tumor necrosis factor alpha (TNF-α), a cytokine that has been shown to play several prominent roles in a number of inflammatory diseases of the CNS (Gehrmann et al., Brain Res. Rev., 20: 269–87, 1995). TNF-α and IL-1 induce astrocytes to produce and secrete several cytokines, including TNF-α and granulocyte-macrophage colony stimulating factor (GM-CSF). Reactive microglia, but not astrocytes, also synthesize and secrete interleukin-3 (IL-3). GM-CSF, IL-3 and interleukin-4 (IL-4) are potent mitogens for MNPs (Giulian et al., J. Neurosci., 12: 4707–17, 1988; Giulian et al., Dev. Neurosci., 16: 128–36, 1994; Gebicke-Haerter et al., J. Neuroimmunol. 50: 203–14, 1994; Lee et al., Glia 12: 309–18, 1994; and Suzumura et al., J. Neuroimmunol., 53: 209–18, 1994). Physiologically, a positive feedback loop is established whereby proliferating MNPs produce more astroglial factors, which leads to glial scarring at the site of injury. The astroglial scar seals the wound at the site of injury, but may eventually prevent axonal regeneration of the surrounding neurons.
MNPs also secrete a number of neurotoxic agents that appear to exert their effects via the excitatory amino acid N-methyl-D-aspartate (NMDA) receptor. These neurotoxins include aspartate, glutamate, and quinolinic acid. The first two compounds are found in elevated concentration in models of traumatic brain injury (Faden et al., Science 244: 798–800, 1989; and Panter et al., Ann. Neurol., 27: 96–99, 1990), and quinolinic acid is found in models of spinal cord contusion injury (Blight et al., Brain Res., 632: 314–16, 1993; and Popovich et al., Brain Res., 633: 348–52, 1994). Another neurotoxic NMDA receptor ligand has been reported that appears to be specific for neurons, but has no effect on astroglia or oligodendroglia (Giulian et al., J. Neurosci., 13: 29–37, 1993; and Giulian et al., J. Neurosci. Res., 36: 681–93, 1993). In addition, a neurotoxic amine (Ntox) has been shown to be produced from microglia and peripheral MNPs isolated from HIV-1 positive patients (Giulian et al., J. Neurosci., 16: 3139–53, 1996).
Activated microglia and MNPs release several other harmful substances, including proteinases, reactive oxygen species, and nitric oxide (NO) (Hartung et al., J. Neuroimmunol., 40: 197–210, 1992; and Banati et al., Glia 7: 111–8, 1993; and Ali et al., Adv. Rheumatol., 81: 1–28, 1997). Proteinases may directly degrade myelin and have been implicated in the proteolysis of extracellular matrix proteins (Hartung et al., J. Neuroimmunol., 40: 197–210, 1992; and Romanic et al., Brain Pathol., 4: 145–46, 1994). Thus, the elevated release of MNP-derived proteases appears to contribute to the breakdown of the extracellular matrix and myelin, thereby widening the zone of secondary tissue damage. Also, reactive oxygen intermediates are released by microglia in response to interferon-gamma (IFN-γ) and TNF-α. These oxygen radicals are responsible for lipid peroxidation, which leads to the breakdown of cell membranes, the specific targets being neurons, oligodendrocytes, and the myelin sheath itself. Human microglia may regulate the production of NO by astrocytes by providing IL-1, IFN-γ and TNF-α (Chao et al., J. Leukoc. Biol. 1: 65–70, 1995).
MNPs produce, secrete, and respond to several cytokines, including IL-1, TNF-α, IL-3, IL-4, GM-CSF, and IFN-γ. These cytokines can modulate most functions of MNPs, particularly the expression of cell surface markers on MNPs. In vitro studies have demonstrated that TNF-α is directly cytotoxic to oligodendrocytes and stimulates microglial phagocytosis of myelin (Zajicek et al., Brain 115: 1611–31, 1992; and Soliven and Szuchet, Int. J. Dev. Neurosci., 13: 351–67, 1995). In addition, TNF-α has been implicated in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and several other demyelinating diseases (Selmaj et al., J. Neuroimmunol., 56: 135–41, 1995; Renno et al., J. Immunol., 154: 944–53, 1995; Redford et al., Brain, 118: 869–78, 1995; Probert et al., Proc. Natl. Acad. Sci. USA, 92: 11294–8, 1995; and Probert et al., J. Leukoc. Biol., 59: 518–25, 1996).
GM-CSF, IL-3, and IL-4 are potent mitogens for MNPs (Giulian et al., J. Neurosci., 12: 4707–17, 1988c; Giulian et al., Dev. Neurosci., 16: 128–36, 1994; Gebicke-Haerter et al., J. Neuroimmunol. 50: 203–14, 1994; Lee et al., Glia 12: 309–18, 1994; and Suzumura et al., J. Neuroimmunol., 53: 209–18, 1994) and are thought to induce a more rapid phagocytosis of myelin (Giulian et al., J. Neurosci., 12: 4707–17, 1988c and Smith, M. E., J. Neurosci. Res., 5: 480–487, 1993), which contributes to the pathogenesis of autoimmune inflammatory diseases (Giulian et al., J. Neurosci., 12: 4707–17, 1988c; Giulian et al., Dev. Neurosci., 16: 128–36, 1994; Gebicke-Haerter et al., J. Neuroimmunol. 50: 203–14, 1994; Lee et al., Glia 12: 309–18, 1994; Suzumura et al., J. Neuroimmunol., 53: 209–18, 1994; and Smith, M. E., J. Neurosci. Res., 5: 480–487, 1993). For example, MNP-specific up-regulation of TNF-α receptors has been demonstrated in AIDS patients (Dickson et al., Glia 7: 75–83, 1993; and Sippy et al., J. Acquir. Defic. Syndr. Hum. Retrovirol., 10: 511–21, 1995) and up-regulation of GM-CSF receptors has been demonstrated in an animal model of facial nerve injury (Raivich et al., J. Neurosci. Res. 30: 682–6, 1991). In addition, newly activated microglia and infiltrating macrophages increase the expression of the low density lipoprotein (LDL)/macrophage scavenger receptor in CNS trauma or disease (Christie et al., Am. J. Pathol., 148: 399–403, 1996; Elkhoury et al., Nature 382: 716–19, 1996; Giulian, D., J. Neurosci. Res., 18: 155–171, 1987; Giulian et al., J. Neurosci., 13: 29–37, 1993a; and Bell et al., J. Neurocytol., 23 605–13, 1994), which is thought to account for increased phagocytotic activity in these conditions.
MNPs and leukocytes are also implicated in the pathophysiology (which involves secondary tissue damage) associated with several non-CNS inflammatory diseases, including various neoplastic, skin, eye, renal, pulmonary and inflammatory joint diseases. Cytokines and chemokines are instrumental in modulating these responses (Furie and Randolph, Am. J. Pathol., 146: 1287–301, 1995; Bagglolini et al., Adv. Immunol., 55: 97–179, 1994; Schall et al., Current Biol., 6: 865–73, 1994; Howard et al., Trends Biotechnol., 14: 46–51, 1996; Strieter et al., J. Immunol., 156:3583–86, 1997; Taub et al., Ther. Immunol., 1: 229–46, 1994; Driscoll et al., Environ. Health Perspect., 105: Suppl 5: 64: 1159–64, 1997).
In solid tumor disease, MNPs have been shown to induce tumor angiogenesis (Leek et al., J. Leukoc. Biol., 56: 423–35, 1994; Sunderkotter et al., J. Leukoc. Biol., 55: 410–22, 1994) and have been found to be the major component of the lymphoreticular infiltrate of various forms of solid tumor, and close to 50% of the cell mass in breast carcinomas (Lewis et al., J. Leukoc. Biol. 57:747–51, 1995).
MNPs, including microglia, are also implicated in the pathogenesis of eye diseases including proliferative vitreoretinal retinopathies (Weller et al., Exp. Eye Res., 53: 275–81, 1991; Charteris et al., Ophthalmology, 100: 43–46, 1993) as are elevated levels of cytokines and chemokines, including IL-2, IL-6, IFN-γ, IL-8, and MCP-1 (Abu el Asrar et al., Am. J. Ophthalmol., 123: 599–606, 1997; Aksunger et al., Ophthalmologica, 211: 223–5, 1997; Kernova et al., Eur. J. Ophthalmol., 7: 64–67, 1997). The observations described above demonstrate that a number of inflammatory disease states, including the pathology of spinal cord injury, are associated with the proliferation, migration, or physiological activity of cells types that promote secondary tissue damage.
Treatment of Secondary Tissue Damage and Other Inflammatory Pathologies
The present treatment of secondary tissue damage and other associated disease states and inflammatory disease states is not well developed. Animal models have demonstrated that colchicine treatment decreases the number of MNPs in damaged tissue and helps to block astrogliosis and neovascularization in addition to the inhibition of phagocytosis and secretory functions (Giulian et al, J. Neurosci., 9: 4416–29, 1989; Giulian et al., Ann. Neurol., 27: 33–42, 1990; and Giulian et al., J. Neurosci., 13: 29–37, 1993). Colchicine, however, is not a selective toxin, and, consequently, it is not considered a viable therapeutic for the treatment of humans. Current pharmacological approaches to the treatment of SCI and prevention of secondary tissue damage center around single biochemical events that occur at the cellular level, for example, inhibiting the cytotoxic actions of excitatory amino acids or reactive oxygen species using NMDA antagonists and free radical scavengers (Faden et al, Trends Pharmacol Sci 13: 29–35, 1992; and McIntosh, T. K., J. Neurotrauma, 10: 215–61, 1993). Few drugs have demonstrated a profound effect on secondary tissue damage. The drugs currently used to address secondary damage in SCI are the steroid methylprednisolone and its synthetic 21 aminosteroid (lazaroid) derivatives (e.g., trisilazad), which act as oxygen free radical scavengers. These drugs are used to inhibit membrane lipid peroxidation. The unwanted side effects of lazaroids, however, are believed to include the induction of gliosis, which has been observed in one animal model of SCI (Gonzalez-Deniselle et al., Cell Mol. Neurobiol., 16: 61–72, 1996), and loss of motor and sensory function as observed in humans with penetrating wounds to the spinal cord (Prendergast et al., J. Trauma, 37: 576–9, 1994). Steroids are also the therapeutic drug of choice for most inflammatory diseases, but their beneficial effects are largely hindered by debilitating side effects, so that long term steroid treatment is not a viable clinical option. Thus, none of the available treatments satisfactorily treat these diseases and disorders.
Hence, there is a need for a more encompassing approach to effectively treat inflammatory disease states associated with the proliferation, migration and/or physiological activity of cells that promote inflammatory responses, including secondary tissue damage, and to treat secondary tissue damage. Therefore, it is an object herein to provide such treatments.